Conventionally, processes of bonding a component to a flat panel display (hereinafter referred to as flat panel) via an anisotropic conductive material or a film of bonding material (hereinafter referred to as anisotropic conductive film or ACF) includes, for example: an ACF application process in which anisotropic conductive film is applied to an edge portion of the flat panel; a preliminary press bonding process in which an electrode of the component and an electrode formed on the flat panel are matched and the electrode of the component is preliminarily bonded to the electrode of the flat panel; and a press bonding process in which the electrode of the component is pressed to the electrode on the flat panel with a pressing force larger than the force used in the preliminary press bonding process so as to bond the electrode of the component to the electrode on the flat panel.
Then, in order to bond such component to the flat panel, it is necessary to precisely match positions of the electrode of the component and the electrode on the flat panel. Thus, for example, a component bonding method is disclosed in which: first, the component is preliminarily press bonded to the flat panel; a bonding state of recognition marks on the flat panel and on the component is examined from a side opposite to the side where the component is bonded so as to measure a position displacement amount between the component and the flat panel; and this amount is fed back to the next preliminary press bonding process (for example, refer to Patent Reference 1).
FIG. 1 is a flowchart showing an operation procedure of the component bonding method shown in Patent Reference 1.
As shown in the present diagram, after performing a panel input process (S2201), the following processes are performed: an ACF application process (S2202); a preliminary press bonding process in which a position of an electrode on a panel and a position of an electrode of a component are matched (S2203); a bonding recognition process in which the position when the electrode of the component is bonded to the electrode of the flat panel is recognized (S2204); and a position displacement amount calculation process in which an amount of position displacement in the aforementioned bonding process is calculated based on the recognition in the bonding recognition process (S2205).
Then, when the position displacement amount is equal to or more than a predetermined threshold, the amount is fed back as a correction amount for correcting the position displacement in the preliminary press bonding process (S2206). Then, a press bonding process in which the electrode of the panel is bonded to the electrode of the component (S2207) and a panel storage process (S2208) are performed, and the processes are ended.
Note that FIGS. 2A, 2B, and 2C are reference diagrams of recognition marks for recognizing a position of the electrode formed on the component and the flat panel. In the bonding recognition process in FIG. 1 (S2204), a bonding recognition device, such as a camera, recognizes: a recognition mark 2301 provided on a TAB board, as shown in FIG. 2A; and recognition marks 2302 provided on the component, as shown in FIG. 2B. In the position displacement amount calculation process in FIG. 1 (S2205), ΔX and ΔY which are the position displacement amounts as shown in FIG. 2C are calculated.
Patent Reference 1: Japanese Laid-Open Patent Application No. 8-330393
However, in the method according to Patent Reference 1, there is a problem that when the position displacement amount is measured by recognizing the recognition marks on the component and on the flat panel on which the preliminary press bonding process has been performed, it is not possible to recognize whether or not the electrode of the component is precisely bonded to the electrode on the flat panel in which the press bonding process has been performed.
In other words, even when the positions of the electrode on the flat panel and the electrode of the component are matched using each of the recognition marks, there are cases where the state in which the electrode of the component is bonded to the electrode on the flat panel varies between the preliminary press bonding process and the press bonding process due to external factors, such as a temperature of the environment, a degree of parallelism of a pressing device which presses the component, and a degree of parallelism of a backup stage pressing device at the flat panel side. In such cases, even when the position is corrected using the position displacement amount obtained in the preliminary press bonding process, the position correction may not always be appropriate one in the press bonding process.
Furthermore, in the component bonding method in Patent Reference 1, a position displacement amount is corrected using the recognition marks on the flat panel and the component. Thus, for example, in the case where the position of the electrode on the flat panel and the position of the electrode of the component are displaced relative to the positions of each of the recognition marks, even when the position of the electrode on the flat panel and the position of the electrode of the component are matched with respect to each of the recognition marks, there is a problem that the actual bonding is not appropriately performed.
In particular, in the manufacturing process, the distance between electrodes on the flat panel and the distance between electrodes of the component are kept almost constant. However, during a period after manufacturing the flat panel until the actual bonding process, due to the peripheral environment, the operation environment, and the like, there are cases where the position of the electrode on the flat panel and the position of the electrode of the component are displaced relative to the position of each of the recognition marks. In such cases, even when the positions of the electrodes on the flat panel and of the component are matched using the recognition marks which indicates each of the reference positions, there is a problem that it is not possible to precisely match the position of the electrode of the component and the position of the electrode on the flat panel.
Furthermore, since conventionally, the size of the component which is bonded to the flat panel is relatively large, when the electrode of the component is bonded to the electrode on the flat panel with a certain amount of position displacement, a defective bonding has never occurred. However, in recent years, with the progress in miniaturization and high precision of components, much higher bonding precision is required. For example, a diameter of a conductive particle included in an anisotropic conductive film is approximately 5 μm, and the length is being reduced. In addition, the dimension of a line which is a width of an electrode and a space which is a gap between electrodes are becoming such narrower as to be equal to or less than 20 μm. With such miniaturization, further improved bonding precision is required.
Furthermore, since a preliminary press bonding device and a press bonding device operate independently from each other in the conventional component mounting apparatus, the process in which the position displacement amount in the press bonding process is fed back to the preliminary press bonding process as the correction amount has not been achieved yet.
The present invention is to solve the aforementioned problems, and the object is to provide a component bonding method with higher bonding precision, when an electrode of a component is bonded to an electrode formed on a flat panel.
Furthermore, another object is to provide a component bonding method using a new position correction method which is other than the position correction method based on the position recognition using recognition marks formed on the component and the flat panel.